1. Field of the Invention
The present invention relates to a sheet processing apparatus, a control method for controlling such a sheet processing apparatus, and a storage medium.
2. Description of the Related Art
Some of the sheet processing apparatuses, which have been known in the art, are provided with a sheet stacking portion designed like a stacking tray in a stacker device that stacks sheets therein, where sheets are stacked on each of the sheet stacking portion (see, for example, Japanese Patent Laid-Open No. 2008-150204).
To stack a sheet on the stacking portion, such a sheet processing apparatus employs an abutting member because of maintaining the stability of a sheet to be stacked on the stacking portion. Specifically, when ejecting a sheet, the abutting member is moved to a position at a distance corresponding to the length of the sheet from a paper ejection port in the conveyance direction. Then, the sheet to be ejected from the paper ejection port is abutted to the abutting member to stack the sheet by dropping the sheet to the stacking unit with the own weight of the sheet.
In addition, one of the conventional sheet processing apparatuses is designed so that an abutting member can change its position depending on the type of a sheet. Such a kind of the sheet processing apparatus prevents an ejecting sheet from jamming into an ejection port by changing the position of an abutting member or preventing an ejected sheet from protruding from a stacking unit.
For example, there is a need of changing the position of the abutting member when ejecting a sheet of A4 standard paper and when ejecting an A4 tab sheet. Such a change in position of the abutting member may reduce the possibility of causing the tab of the tab sheet to jam into the ejection port or prevent the tab of the tab sheet from protruding from the stacking tray.
However, when determining the position of the abutting member depending on the type of the sheet, the abutting member is located at any of different positions depending on different sheet types. Thus, the stacked sheets being abutted on the abutting member may be displaced from their suitable positions. Therefore, the stability of the stacked sheets tends to be reduced.